Reading guides like this one will serve a number of different purposes throughout the course. One fairly constant role will be to call your attention to ideas and issues in the material you read that seem to me worthy of discussion. However, I do not intend to limit our discussion to these, so you should certainly look for other ideas or issues of interest to you. In some cases, reading guides will provide background information to set what you read in context or to highlight some issues that might not otherwise stand out. And I’ll occasionally incorporate short quotations as supplements to the reading assignment on the syllabus.
In his first chapter, Carnap introduces the concept of a scientific law and discusses a few issues concerning it. Although he will turn to somewhat different topics in the chapters immediately following this one, many of the issues in it will reappear in some form later in the book.
When thinking about the idea of law as Carnap describes it, focus especially on the distinction he makes between laws and facts. Then ask yourself why he thinks laws, understood in this way, are so important. Also, ask yourself whether you agree with him. One thing to ask in this regard is whether his description of laws fits scientific laws that you are familiar with. If you can think of an example where it doesn’t seem to fit, try to think what he might say if someone asked him about that example.
Part of what makes laws important for Carnap are their function in explanation and prediction. Of course, think through what he has to say about this (he has a good deal more to say about explanation than prediction) and, again, whether you agree with him. I’ll go on to suggest some ways of thinking about a couple of the issues he touches on concerning explanation.
One issue concerns what he calls “fact explanations” (p. 7). As he says, these are common in everyday life, and other philosophers have argued that such explanations are not, as he says, “really” law explanations. Here is a quotation from someone who argued this:
If you reach for a cigarette and in doing so knock over an ink bottle which then spills onto the floor, you are in an excellent position to explain to your wife how that stain appeared on the carpet, i.e., why the carpet is stained (if you cannot clean it off fast enough). You knocked the ink bottle over. This is the explanation of the state of affairs in question, and there is no nonsense about it being in doubt because you cannot quote the laws that are involved, Newton’s and all the others; in fact, it appears one cannot here quote any unambiguous true general statement, such as would meet the requirements of the deductive model.
Michael Scriven, “Explanations, Predictions, and Laws” in Minnesota Studies in the Philosophy of Science, vol. 3 (Minneapolis, University of Minnesota Press, 1962), p. 198.
The view that Carnap supports is sometimes called the “deductive-nomological” model of explanation and sometimes the “covering-law” model. Carnap is not the only one who has supported it—Scriven focuses his criticism on an account of it by Carl Hempel and Paul Oppenheim—and Scriven is not the only one who has opposed it.
Carnap mentions the views of Ernst Mach (1838-1916) on p. 12. Mach is as good an example as anyone of a positivist, and a sense of his views can help fill out the meaning of that term. Here’s an example:
Nature is composed of sensations as its elements. Primitive man, however, first picks out certain compounds of these elements—those namely that are relatively permanent and of greater importance to him. The first and oldest words are names of “things.” Even here, there is an abstractive process, an abstraction from the surroundings of the things, and from the continual small changes which these compound sensations undergo, which being practically unimportant are not noticed. No inalterable thing exists. The thing is an abstraction, the name a symbol, for a compound of elements from whose changes we abstract. The reason we assign a single word to a whole compound is that we need to suggest all the constituent sensations at once. When, later, we come to remark the changeableness, we cannot at the same time hold fast to the idea of the thing’s permanence, unless we have recourse to the conception of a thing-in-itself, or other such like absurdity. Sensations are not signs of things; but, on the contrary, a thing is a thought-symbol for a compound sensation of relative fixedness. Properly speaking the world is not composed of “things” as its elements, but of colors, tones, pressures, spaces, times, in short what we ordinarily call individual sensations.
…
… In speaking of cause and effect we arbitrarily give relief to those elements to whose connection we have to attend in the reproduction of a fact in the respect in which it is important to us. There is no cause nor effect in nature; nature has but an individual existence; nature simply is. Recurrences of like cases in which A is always connected with B, that is, like results under like circumstances, that is again, the essence of the connection of cause and effect, exist but in the abstraction which we perform for the purpose of mentally reproducing the facts.…
…
… Rules for the reconstruction of great numbers of facts may be embodied in a single expression. Thus, instead of noting individual cases of light-refraction, we can mentally reconstruct all present and future cases, if we know that the incident ray, the refracted ray, and the perpendicular ie in the same plane and that sin α / sin β = n.… The economical purpose here is unmistakable. In nature there is no law of refraction, only different cases of refraction. The law of refraction is a concise compendious rule, devised by us for the mental reconstruction of a fact, and only for its reconstruction in part, that is, on the geometrical side.
Ernst Mach, The Science of Mechanics (LaSalle, Ill.: Open Court, 1960), pp. 579, 580 582.
It is characteristic of Carnap to present Mach’s views as having less radical implications than these quotations might suggest. You should ask yourself (now and as you read more of him) how close Carnap’s views are to the ones expressed in this quotation.
One final issue concerns the relation of mathematics to science. Think about what he says about mathematics on pp. 9-12 (he makes his claims about mathematics by analogy with some claims about logic) and ask yourself whether you would agree that the laws of mathematics “tell us nothing whatever about the world” (p. 9).